The taking of fluid specimens for laboratory analysis is an important diagnostic tool in the treatment of medical diseases and ailments. It is clearly evident that specimens should be as free as possible from any possible secondary contamination, be it from the area from which the specimen is taken or the ambient conditions external to the subject but through which the specimen collecting device must be moved. Conventionally, fluid specimens are withdrawn from a subject by syringe, having generally a hypodermic needle attached thereto for penetration of the subject. Often there is a need to introduce the collected specimen to a specimen maintenance agent, reagent, or culture media to induce specimen growth, specimen identification, or sustain the collected specimen's values constant and viable for subsequent laboratory procedures. It is not generally desired to introduce the specimen agent, reagent, or culture media, nor a specimen to which any of these media have been applied to a patient, the matter of toxicity being the question. Specimens may be body liquids such as blood or urine, or other tissue fluids, or may be anaerobic specimens collected from various organs within the body, or may consist of water or other non-body fluids.
In some institutions, the practice has been to place a cork or stopper over the end of the needle after it is withdrawn from the subject in order to seal and protect the collected specimen, and then the syringe is carried to the laboratory. In other situations, the syringe collected specimen is injected through a rubber stopper into an otherwise sealed vial or tube. These vials and tubes often containing a specimen agent are then sent to the laboratory.
Sometimes, a specimen is ejected from the syringe into a tube containing specimen maintenance media which tube is then closed and taken to the laboratory, sealing and maintenance of the specimen being of primary importance in preserving the viability of the specimen and its quantitative values.
In attempts to increase the viability of the specimen and further minimize secondary contamination, there has been developed a vacuum operated system for taking liquid samples. The system comprises a bottle often containing a specimen maintenance or culture medium which is evacuated and then sealed with a rubber diaphragm to maintain the negative pressure within the container. To use such a device, use is made of a special hypodermic needle which may be considered as double ended. One of the needles is inserted into the subject and the other end of the needle is then inserted through the rubber diaphragm. The negative pressure in the container automatically draws fluid into the container. The draw is sudden and uncontrollable, and has been known to cause veins to collapse. Also, the vacuum within the container may be less than necessary to withdraw the desired amount of fluid. Because the interior volume of such containers cannot be variably controlled, such containers are made available in many capacity sizes such as 5, 7, 10, 15, and 20 cc capacities, resulting in the need to stock many sizes of the containers to meet varying requirements. Many of these types of containers are sold in a non-sterile state, and thus the institutions utilizing them must subject them to sterilization or run the risk of contaminated cultures. It has been noted that in many instances the autoclaving for sterilization reduces the amount of negative pressure within the container, and such containers do not provide the means to expel the fluid within them.
In the recent developments in the field of collecting devices, is a syringe type device which is shown in U.S. Pat. No. 4,043,336. This patent is a hollow body member with a plunger therein. The so-called closed end of the end portion of the body member has a circular disk adhesively secured near the closed end, but providing space for another disk between the secured disk and the interior surface of the closed end. The second disk contains a nipple which extends outwardly through a slot in the closed end. Both disks have an orifice in each, and each movement of the disk with the nipple in the slot and the closed end of the syringe brings the two orifices into communication or out of communication. This device may contain an exterior protrusion on the side of the body member into which may be placed some form of medium for automatic and instant application to the specimen as it is being collected. The design of this device does not provide for the separation of the self-contained specimen agent from the fluid in the chamber of the syringe.